Internal combustion engines



Nov. 27, 1956 A. HILPERT 2,771,861

INTERNAL COMBUSTION ENGINES Filed July 22, 1950 INVENTOR. Alfons H 4GuULUMQ/L ATTORNEBS United States Patent 2,771,861 I INTERNAL COMBUSTIONENGINES Alfons Hilpert, Hamburg-Blankenese, Germany Application July 22,1950, Serial No. 175,338

1 Claim. (Cl. 123-32) This invention relates to internal combustionengines. The object of the present invention is to effect a shorteningof the period of combustion or to obtain a more rapid and sudden rise ofpressure in internal combustion engines of all kinds whether they usesolid, liquid or gaseous fuels. This result is obtained, in accordancewith the invention, by producing a jet of flame having a velocitybetween 80 metres per second and the velocity of sound or above thiswhich increases the velocity of combustion in the chamber above thepiston up to the velocity of the jet. The production of the jet of flamecan be eflfected by causing a mixture of fuel and air to be brought tocombustion by means of a sparking plug or other ignition devices withincrease of temperature and pressure in a relatively small auxiliarychamber which is in communication with the compression chamber of thecylinder through small openings or passages, so that, owing to theincreased pressure produced, the combustion gases are forced into thecompression chamber through the small openings in the form of jets offlame having a high velocity which in some cases may be as great as thevelocity of sound.

The velocity of the jet of flame can be increased in stages by arrangingtwo or more auxiliary or side chambers in series, for example, in such amanner that on increase in pressure due to combustion takes place in thefirst chamber by ordinary ignition, and the pressure is increasedfurther in the second chamber and so on up to the combustion chamber ofthe cylinder, in such a manner that a jet of flame passing throughsuitably dimensioned openings with accelerated velocity causes the speedof combustion to increase from chamber to chamber. A further increase inthe effect aimed at can also be obtained by producing a number of jetsof flame directed towards one another which, by impinging on the gasabove the movable piston effects its combustion or detonation.

Since the combustion produced by the jet of flame takes place on the onehand in the direction of movement and with the velocity of the flame,and on the other hand also proceeds in all directions with the normalvelocity of about 80 metres per second, the total combustion velocity isequal to the resultant of the two. The increase in the rate pressureincrease produces a dynamic pressure which is manifested mainly in anincrease in pressure and temperature and in an elastic blow on thepiston, this eflect being the more noticeable the more quicklycombustion takes pllice.

The means for carrying the method of the invention into etfect may bedivided into those for use with existing two-stroke and four-strokecycle engines and those for new constructions. In the case of existingengines the necessary additional devices comprising the auxiliarychamber, or chambers, can be adapted to suit the form of the combustionchamber and the requirements of the invention, whereas in the case ofnew constructions the form or design of the combustion chamber can beadapted to suit the requirements of the invention.

In all the cases, the advantage of an economy of fuel or an increase inthe power ofthe internal combustion engine is obtained.

A device suitable for carrying out the method of the invention isillustrated, by way of example, in the accompanying drawings in which: 7t v Figure 1 is a complete vertical section through the central axis ofthe cylinder at right angles to the crank shaft of an upright two-strokecycle engine with a valve between the auxiliary chamber and the maincombustion chamber, for obtaining different degrees of compression inthe two chambers and for effecting ignition in the auxiliary chamber.

Fig. 2 is a section through the wall separating the two combustionchambers.

Fig. 3 illustrates a perforated plate, the openings of which may beclosed by a controlled valve located between the main chamber and theauxiliary chamber.

Figure 1 shows a complete vertical section through the central axis ofthe cylinder at right angles to the crank shaft of an upright two-strokecycle engine having a controlled valve 49 between the main chamber 47and the auxiliary combustion chamber 46, for obtaining different degreesof compression in the two chambers, for enabling self-ignition to takeplace in the chamber 47.

The two chambers are separated by the valve 49 and a wall 50. Alsoseparate water cooling can be provided for the partition between the twochambers and the bottom but this may be dispensed with. The injection offuel is effected from above through the high pressure nozzle 48 whichproduces a jet directed towards the left into the closed combustionchamber 46 in which the compression pressure is about 20 atmospheres andalso produces a jet directed towards the right into the chamber 47 wherea compression pressure of about 35 atmospheres is produced in order toeffect self-ignition. During compression the control valve 49 remainsopen until a pressure of about 20 atmospheres is reached whereupon thevalve is positively closed and the remainder of the compression strokeincreases the pressure only in the chamber 47 up to about 35atmospheres. During the injection of the fuel into both chambers whichtakes place at the upper dead point or shortly before this is reached,only an atomised mixture is produced in the combustion chamber 46because the pressure and temperature are not suflicient forself-ignition, whereas in the chamber 47 self-ignition oc curs as indiesel engines at a compression pressure of about 35 atmospheres. Thevalve 49 is held closed up to this moment and is then positively opened.During the equalisation of pressure which then occurs through the valveport, a maximum pressure of about 60 atmospheres in the chamber 47 isopposed to a pressure of about 20 atmospheres in the combustion chamber46, so that, on discharge a jet of flame having the speed of sound isproduced, and the pressure at the orifice is the so-called criticalpressure which amounts to about the half, i. e. to about 30 atmospheres.Therefore, the jet of flame will spread out to all sides in theauxiliary combustion chamber with maximum velocity and the dynamicpressure increase to a maximum and be converted into heat. The valve 49may in some cases open and close a number of openings 51 as indicated inFigures 2 and 3. Any suitable means may be used to close the valve 49,while the spring 52 holds it open.

I claim:

An internal combustion engine having an auxiliary chamber and a maincombustion chamber, a common high pressure fuel injection nozzle for themain combustion chamber and the auxiliary chamber, an opening betweenthe main combustion chamber and the auxiliary chamber, a valve in themain combustion chamber for closing the opening between the maincombustion chamvalve for closing i ermi e whe a rareleternainei.

compression pressure is reached, said valve being positively openedafter self-ignitidn of the fuel-air mixture in the maincembustioncharnber. j

References Cited in the file of UNITED STATES PATENTS; V Lemaire Feb.14,1922 q s n F 24 11 lmelz 1,981,412 2,000,903 2,019,298 2,503,186

Lightfbot 'Aug. 19, 1924 1195s,? -,-.V-A-, Ma 122.1.

Fritsche Nov. 20, 1934 Lehmann Mar. 14, 1935 Fischer Oct. 29, 1935Ziegler Apr. 4, 1950 FOREIGN PATENTS Great Brifairr Feb. 5, 1908 Great.Britain, lune-25, 1912

